Method and means for acoustic energy conversion

ABSTRACT

A method of converting acoustic energy to another form of energy establishes a magnetic field in an electrically conductive fluid medium. Acoustic energy is passed into the electrically conductive fluid medium and converted therein into another form of energy. A conversion device receives acoustical energy passed into an electrically conductive fluid medium which is under the influence of a magnetic field. The energy passed into the electrically conductive fluid medium causes electric currents in the fluid which are dissipated in the magnetic field and transformed to thermal energy which is dissipated by the device.

lU-ll FIFSEIQZ United States Patent Porter, Jr.

[4 1 Sept. 18,1973

METHOD AND MEANS FOR ACOUSTIC ENERGY CONVERSION Don B. Porter, Jr., P.0. Box 115, Neodesha, Kans. 66757 Filed: May 27, 1971 Appl. No.: 147,347

Inventor:

US. Cl 2l9/10.65,' 219/10.5l, 219/284, 310/2, 310/11 Int. Cl. H051)9/00, H02k 45/00 Field of Search 219/10.51, 10.65, 219/284, 375, 376;310/2, 9.1, 11

References Cited UNITED STATES PATENTS 8/1937 Littlefleld 219/l0.65 x 9/1 956 Banta 2/1970 Burgo et al. 310/91 Primary Examiner-R. F. StaublyAttorney-John H. Widdowson [5 7] ABSTRACT A method of convertingacoustic energy to another form of energy establishes a magnetic fieldin an electrically conductive fluid medium. Acoustic energy is passedinto the electrically conductive fluid medium and converted therein intoanother form of energy. A conversion device receives acoustical energypassed into an electrically conductive fluid medium which is under theinfluence of a magnetic fleld. The energy passed into the electricallyconductive fluid medium causes electric currents in the fluid which aredissipated in the magnetic field and transformed to thermal energy whichis dissipated by the device.

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i WW METHOD AND MEANS FOR ACOUSTIC ENERGY CONVERSION In the prior art ofacoustic energy disipation and the art of thermal energy production nomethod or device is known that converts acoustic energy specificallyinto thermal energy.

In the herein disclosed invention a method and four preferred specificembodiments of a device to convert acoustic energy to thermal energy areprovided. The energy conversion method generally includes theestablishment of a magnetic field in a conductive fluid, passingacoustic energy into it and converting it to another form of energy andinto thermal energy. The energy conversion device generally includes anelectrically conductive fluid medium in an enclosure with a magneticfield to act on the fluid medium. A means is provided to produceacoustic energy in the fluid medium so it causes molecular, particle,motion in the fluid, and means are provided to transfer thermal energyfrom the energy conversion device.

In the herein described preferred specific embodiments of this inventionthe method of the invention is utilized in each of them. The method ofconversion of energy of this invention is similarly employed in each ofthe hereafter described means of energy conversion and is an essentialfactor in their operation. The conversion method of this inventiongenerally includes the establishing of a magnetic field in anelectrically conductive fluid medium, passing acoustic energy into thefluid medium converting it into another form of energy and into thermalenergy. The conversion method of this invention is generally adapted tothe means of this invention and specifically adapted to the individualpreferred specific embodiments of means of this invention as will beapparent from the hereafter description.

In one preferred specific embodiment of this invention a structureborneacoustic energy conversion device, (l), is provided for the directtransmission of structurally borne acoustic energy into thermal energy.A foundation mount mountable on a fixed surface has a cavity thereinenclosing the fluid medium, and the magnetic field generator. A pistonin the cavity in contact with the fluid provides transmission ofacoustic energy to the fluid medium, and the outer surface of thefoundation mount serves to disipate and radiate the converted thermalenergy. The piston is secured to an acoustic energy generating structureor an acoustic energy generating device. Components of the device areconstructed to be so impedance mismatched that acoustic energy receivedby the piston will be transmitted to the fluid medium and not to thestructure of the device.

In a second preferred specific embodiment of this invention, an airborneacoustic energy conversion device, (2), is provided for the directtransmission of acoustic energy from air or other either gaseous fluidand/or liquid fluid into thermal energy. This device has an acousticallyclear impedance envelope to be placed in the acoustic energy containingfluid that is adapted to pass the acoustic energy through it to theelectrically conductive fluid medium inside the envelope. The magneticfield generator is contained in the envelope and acts in conjunctionwith the electrically conductive fluid to convert the acoustic energy tothermal energy. Thermal energy converted by this device is disipated byeither radiation and/or conduction from the envelope.

In a third preferred specific embodiment of this invention a fluid-borneacoustic energy conversion device, (3), is provided for the directtransmission of acoustic energy from a fluid stream into the fluidmedium for conversion into thermal energy. The enclosure has an acousticfluid passageway therethrough with an acoustically clear membraneseparating it and the fluid medium. The enclosure assembly confines theacoustic passageway and has the magnetic field generator in it. Acousticenergy passes through the membrane into the fluid medium and magneticfield where it is converted into thermal energy. The thermal energy isdisipated from the housing by either radiation and/or conduction as itis converted.

In a fourth preferred specific embodiment of this invention a linearsonar array, (4), is provided to convert fluid borne acoustic energyinto thermal energy and electrical signals from which sonar data may betaken. The linear sonar array is filled with the electrically conductivefluid, has a power line to establish the electromagnetic field in theconductive fluid medium. Pickup units are placed in the electricityconductive fluid to receive and detect acoustic energy as it passes byin the conductive fluid. The pickup units are used to detect electricaleddy-current activity in the fluid in the presence of the magneticfield. The linear sonar array also converts acoustical energy intothermal energy as do the other devices and it is coupled with detectionand analysis equipment.

One object of this invention is to provide a method of convertingacoustic energy into thermal energy.

Still, another object of this invention is to provide a method ofconverting acoustic energy into thermal energy whereby a magnetic fieldis established in an electrically conductive fluid medium and acousticenergy is passed into the fluid medium and therein converted to thermalenergy.

Yet another object of this invention is to provide a method ofconverting acoustic energy to thermal energy wherein an electromotiveforce is established in a fluid medium and acoustic energy passingthrough the fluid medium is converted to thermal energy.

Yet an additional object of this invention is to provide a method ofconverting acoustic energy to thermal energy wherein the conversion canbe detected for analysis.

One object of this invention is to provide an acoustic energy conversiondevice adapted to convert acoustic energy specifically into thermalenergy.

Still, another object of this invention is to provide an acoustic energyconversion device to convert acoustic energy to thermal energy throughthe use of a magnetic field in an electrically conductive fluid mediumby the dissipation of electrical eddy-current activity caused bymolecular, particle motion in the conductive'field.

Yet, another object of this invention is to provide an acoustic energyconversion device in a structural member to thermal energy in the fluidmedium.

Yet, an additional object of this invention is to provide an acousticenergy conversion device to convert acoustic energy carried in a fluidstream to thermal energy in the fluid medium.

Yet another object of this invention is to provide an acoustic energyconversion device to convert acoustic energy carried in a fluid that issubstantially unenclosed to thermal energy in a contained fluid medium.

Yet another object of this invention is to provide an acoustic energyconversion device to convert acoustic energy to thermal energy and toprovide a conversion device to detect electrical eddy-current activityin the fluid medium so that sonar data can be taken.

Various other objects, advantages, and features of the invention willbecome apparent to those skilled in the art from the followingdiscussion, taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a cross-sectional side elevation view of the structureborneacoustic energy conversion device with an actuator and fixed mount;

FIG. 2 is a view of the structureborne acoustic energy conversion devicetaken on line 22 of FIG. 1;

FIG. 3 is a view of the sensitizer filament holder and wall of thestructureborne acoustic energy conversion device taken on line 3-3 ofFIG. 2;

FIG. 4 is a partially cut away perspective view of the airborne acousticenergy conversion device;

FIG. 5 is a cross-sectional view of the airborne acoustic energyconversion device showing a magnet supporting partition member;

FIG. 6 is a view of the airborne acoustic energy conversion device takenon line 66 of FIG. 5;

FIG. 7 is a cross-sectional elevation view of the fluidborne acousticenergy conversion device attached to a fluid conduit;

FIG. 8 is an end view of the fluidborne acoustic energy conversiondevice taken on line 8-8 of FIG. 7;

FIG. 9 is a cross-sectional view of the fluidborne acoustic energyconversion device taken on line 99 of FIG. 7;

FIG. 10 is a diagrammatical view of the linear sonar array acousticalenergy conversion device showing the enclosure, the pick up units andamplifiers;

FIG. 11 is a cross-sectional view of a pick up unit of the linear sonararray acoustic energy conversion device; and

FIG. 12 is a block diagram of an arrangement of analytical equipmentusable to take sonar data from the linear sonar array acoustic energyconversion device.

The following is a discussion and description of preferred specificembodiments of the method and means of acoustic energy conversion ofthis invention, such being made with reference to the drawings whereuponthe same reference numerals are used to indicate the same or similarparts and/or structure. It is to be understood that such discussion anddescription is not to unduly limit the scope of the invention.

Precluding further reference to the drawings and discussion of thepreferred specific embodiments and method of this invention, a generalconceptual and technical example is provided describing the generaloperating principles of this invention. The following example isintended only to illustrate the basic principles on which thehereindescribed invention operates and is not to limit the scope of theinvention.

First, the concepts involved with this invention can be logically andfeasibly described in terms of general and known concepts. When acousticenergy is transmitted through a fluid media, motion of the fluidresults. This motion is a result of particle or molecular disturbance ofthe fluid by the traveling energy waves. When an electrical conductor ismoved through a magnetic field an electromotive force is generated orthe potential of the particle is raised. By using an electricallyconductive fluid media under the influence of a magnetic field andintroducing acoustic energy into this fluid the result will be motion ofthe electrically conductive particles through the magnetic field therebygenerating an electromotive force. Assuming the electrically conductivefluid to have homogeneous characteristics, then the electromotive forcewill result in eddy currents, circulating currents, which will beoriented by the direction of the magnetic field flux and by thedirection of motion of the acoustical energy. As the acoustical energywave passes through the fluid media in the influence of the magneticfield, its energy will be reduced as electromotive force and eddycurrents are generated. The amount of acoustical wave energy reductionis proportional to the power of the electromotive force generated. Whilethe eddy currents are circulating in the influence of the magneticfield, their energy will be dissipated and converted to thermal energyas they move in opposition to the flux of the magnetic field. Energyreduction of the eddy currents is facilitated by the potential of thecharged particles being reduced by their motion against the force of themagnetic field, and by the electrical resistivity of the fluid media.The total result accomplished is that acoustic energy is introduced intoa fluid media and therein converted to thermal energy.

Second, concepts relating to the herein described invention can befurther demonstrated by the use of an example illustrating the energyredistribution which occurs in an acoustic wave in conjunction with thetheoretical feasibility described in the foregoing. Consider anunbounded homogeneous fluid medium having a point source of acousticenergy located therein. When the point source of acoustic energy isactivated to produce a single pulse of energy, a single spherical waveacoustic energy will travel from the point source. The thickness of thespherical wave traveling from the point source is one wave length andthe spherical wave will travel at a velocity equal to the speed of soundin the fluid medium. As the spherical wave travels further from thepoint source, its volume necessarily increases and accordingly itsenergy content per unit volume is decreased though its total energycontent may remain constant. This reduction of energy content per unitvolume is known in sonar technology and is referred to as spreadingloss. As the spherical wave increases in size, there is an energyvelocity radially and since the enrgy content per unit volume is reducedthere is necessarily an energy velocity tangential to the spherical waveor normal to the radial velocity. This energy redistribution occurs inthe spherical wave as a result of these changing energy velocities dueto the normal characteristic wave permutation. Also, any other thingwhich causes a change in the total energy content of the wave willnecessarily cause an energy redistribution within the wave in additionto that described. All energy redistribution within the spherical wavemust result in molecular or particle motion of the fluid in thedirection of the energy redistribution. This molecular or particlemotion is the motion which in an electrically conductive fluid, asdescribed in the feasible and general description supra, will result ineddy currents and ultimately in acoustic to thermal energy conversion.Additionally, the physically different directions of motion of theenergy velocities provides a basis for instrumentation and analysis ofthe acoustic wave.

Referring to the drawings in general FIGS. 1, 2 and 3 show thestructureborne acoustic energy conversion device embodiment, (1), FIGS.4, 5 and 6 show the airborne acoustic energy conversion deviceembodiment, (2), FIGS. 7, 8 and 9 show the fluidborne acoustic energyconversion device embodiment, (3), and FIGS. 10,11 and 12 show thelinear sonar array acoustic energy conversion device, (4), and diagramsof sonar data analysis equipment. All the herein described embodimentsof this invention operate with the same method to convert acousticenergy to thermal energy, however, since the specific structure of eachembodiment is different it will operate slightly differently and themethod necessarily varies slightly with each conversion device as willbe apparent in the following description which has incorporated thereina description of the method.

Referring t FIGS. 1, 2 and 3 of the structurebome acoustic energyconversion device, the device of this embodimenhtl), is generallyindicated at 10 and includes a housing assembly 12 supported on afoundation mount 14, withan actuator member 16 to carry structurallyborne acoustic energy to the device. The foundation mount 14 ispreferrably secured to a solid and substantially immovable surface orthe like. The actuator member 16 is preferably a piece of structure ofsome device that carries acoustical energy, this could conceivably be amachine of same type or anything that structurally carries acousticalenergy. The housing assembly 12 has a cylindrical outer member with acylindrical sidewall 20 and integral bottom 22, the bottom 22 beingsecurable to foundation mount 14. Inside the housingassembly acylindrical cavity 24 is provided to contain the electrically conductivefluid inediurn; it has a cylindrical cavity wall 26. An isolationcylindrical wall 28 is spaced between the cavity wall 26 and the outerhousing wall 20. It is to be noted these walls 20, 26 and 28 areseparated by spaces 30 and 32 and held in parallel relation by inwardlyextending supports on the inside of them. The cavity wall 26 and theisolation wall 28 on the bottom edges contact a resilient spacer 34placed between them and the bottom of the housing 22. The isolation wall28 on the top is secured to a cover 36 that is ring shaped and extendsinward past the cavity wall 26 and isolated from the cavity wall 26 andthe isolation wall 28 by a resilient member 38.

Inside the cavity 24 a reflector member 40 is positioned at the bottomisolated from the cavity wall 26 and the housing bottom 22; atransmitterpiston 42 is positioned at the top of the cavity 24 isolated from thecavity wall 26 and cover 36; and a plurality of sensitizer elements,generally indicated at 44 are confined by the cavity wall 26. Thereflector member 40 is sealed with the cavity wall by an O-ring 40amsupported above the housing bottom on a ring member 48. The uppersurface 50 of the reflector member 40 is concaved outward from thecavity 24, and the reflector member is constructed of material that willreflect any'acoustic energy striking the surface 50 back into the cavity24. The transmitter piston 42 is sealed with the cavity wall 26 by anO-ring 52 and is isolated from the cover 36 by a resilient compressionmember 54. The resilient compression member 54 gives the piston 42 anominal compression force against the fluid in the cavity and isolatesit from the cover 36. On its outer surface the transmitter piston 42 isprovided with a lag to attach the actuator member 16. The sensitizerelements 44 are a plurality of filaments 56 supported in a plurality oflayers spaced through the cavity 24. The filaments 56 are parallel toone another and extend completely across the cavity 24 and are supportedin guide ring assemblies 58 which are shown in detail in FIG. 3 spacedthrough the cavity. Each of the sensitizer elements 44 preferably hastwo layers of filaments-one below the other-supported in individual ringassemblies 58. The layers of sensitizer elements 44 are positioned sothat they are all parallel and the filaments are parallel as can be seenin FIG. 1. The layers of sensitizer elements 44 are connectedelectrically by additional filaments 60 between them which are separatebut appear to cross when seen as in FIG. 1. The sensitizer elements 44are connected to an outside power source through a power line 62attached to a coupler 64 on the housing bottom 22 and wires inside thehousing passing through the reflector member 40 at a potted connector66.

Details of the sensitizer elements mounts are shown in FIG. 3. Thefilaments 56 are mounted in an electrical insulating guide 68 that iscircular in form having the filaments embedded in it. The guide 68 isattached to a band 70 on its outer perimeter. The band 70 is in directcontact with the cavity wall 26 and supports the guide 68. The guide 68and band 70 are preferably constructed of an acoustically clear materialsoas not to impair acoustic energy transmission in the fluid medium,

In actual operation of the structureborne acoustic energy conversiondevice embodiment 10' of this invention, the device is mounted on asubstantially solid foundation or the like, and the actuator member 16is secured to a machine or another acoustic energy carrying device. Thepower line 62 is connected to a direct current electrical power sourceso the sensitizer elements 44 produce a magnetic field in the cavity 24.Acoustic energy is carried to the transmitter piston 42 through theactuator member 16. Acoustic energy carried in the actuator member 16 isbest described, for purposes here, as energy waves which are in effecttransferred directly into the transmitter piston. The transmittor piston42 is designed to transmit the acoustic energy it receives to the fluidmedium contained in the cavity 24. As acoustic energy is transmitted tothe fluid medium, it causes motion of the molecular particles in theelectrically conductive fluid medium in waves corresponding to theenergy waves received from the actuator member 16. Since the molecularparticles are actually electrically conductive particles and are movedthrough the cavity 24 as a result of their excitation by the transmitterpiston, they generate an electromotive force as they move through themagnetic field. Assuming the fluid medium has essentially homogeneouscharacteristics of electrical conductivity, then the electromotive forcewill result in eddy currents, circulating electrical currents, orientedin the direction of the acoustic energy waves. The magnetic field isoriented so the lines of flux are oppositely oriented relative to thedirection of travel'of the acoustic energy waves. As the eddy currentsmove in the direction of the acoustic energy waves, they are opposed bythe magnetic field and the energy of the eddy currents is dissipatedinto thermal energy. Thermal energy in the fluid medium is transferredthrough the fluid to the housing 12 where it is dissipated by conductionand radiation. Any acoustic energy not converted after passing throughthe cavity 24 is reflected by the reflector member 40 back throughthe'cavity 24 to be acted on by the magnetic field.

It is to be noted that in the structure of this device the cavity wall26, isolation wall 28 and housing side wall are constructed to be soimpedance mismatched thus acoustic energy will be contained within thefluid medium. Also, the reflector member 40 is impedance mismatched withthe surrounding structure so it will reflect the acoustic energy waveswhich reach its surface 50. The transmitter piston 42 is impedancematched with the fluid medium so acoustic energy will be transferredfrom the piston 42 to the fluid medium will be maximized. The fluidmedium may be either liquid or gas, either of which proves to beoptimum. The important factor is that the transmitter piston isoptimumly matched with the fluid medium regardless of the specificmaterials. The actual amount of acoustical energy converted to thermalenergy will necessarily depend on several factors including the strengthof the acoustic energy waves, the strength of the magnetic field andtemperature.

In the optimization of all the herein described devices of thisinvention, several factors affecting physical properties of thematerials in the devices are to be noted. First, the acoustical clarityof a material is dependent upon its relation to an ambient fluid incontact with it. A material is considered to be acoustically clear whenit has the same sonic velocity as the ambient fluid in contact with itfor purposes here. The advantage of an acoustically clear material isthat sonic waves will travel through it at the same rate they wouldtravel through the ambient fluid which is in contact with it. Second,the specific fluids necessary to optimize the device will depend uponseveral complex physical factors affecting the fluids, such as impedancematch between the fluids, compressibility, mass density, electricalconductivity and bulk modulus. Two fluids will have an optimum impedancematch when their (bulk modulus/density) ratios are equal. However, foreach device the optimum impedance match will also require considerationof the geometric factors also. Maximizing eddycurrent generationrequires balancing the molecular amplitude and velocity; this is done byadjusting the bulk modulus of the fluid and/or density of the fluid.Maximum power loss is needed to maximize the acoustic to thermal energyconversion; this is done by adjusting the electrical conductivity of thefluid which depends on its molecular structure and ability to transportan electrical charge.

Referring to FIGS. 4, 5 and 6 of the drawings showing the airborneacoustic energy conversion device embodiment of this invention, thisdevice'is generally indicated at 80 and includes an envelope enclosure82 with a plurality of enclosed sensitizer partitions 84 dividing theenvelope enclosure 82 into a plurality of separate cavities 86.

The envelope enclosure 82 is constructed of an acoustically clearmaterial adapted to pass acoustic energy yet retain an electricallyconductive fluid medium within the enclosure between the sensitizerpartitions 84. The sensitizer partitions 84 are rigid membersconstructed of acoustically clear material and have a plurality ofmagnets 88 mounted therein adapted to create the magnetic field. Themagnets 88 are oriented with their north and south poles in the samedirection so the magnetic field will be uniform in direction. Themagnets are spaced on the sensitizer partitions 84 so as to create amagnetic field that is substantially uniform in strength.

The envelope enclosure 82 is preferably rectangular in shape as can beseen in FIG. 4. The sensitizer partitions 84 are parallel and extend thelength of the envelope 82 so the cavities 86 are parallel andsubstantially equal in size. The envelope 82 has sidewalls 90 secured tothe elongated edges of the partitions 84 and other sidewalls 92 securedacross the ends of the sensitizer partitions 84. the remaining envelopesidewall 94 is the sensitizer partitions 84 on the end of the parallelplurality of them. The magnets 88 are preferably high magnetic fielddensity permanent magnet type magnets and as can be seen in FIG. 6secured to opposite sides of the sensitizer partition 84. It is obviousthat the essential magnetic field of this device may also be provided byelectromagnets energized by an external source.

Theairborne acoustic energy conversion device 80 operates on the sametheoretical principals as the aforedescribed structureborne acousticenergy conversion device 10. The airborne acoustic energy conversiondevice 80 is adapted to be supported in a medium of air or other gaseousfluid which is carying acoustic energy. For instance, an acoustic energycarrying gaseous fluid medium might be an engine exhaust, a furnaceexhaust or the air in a room or other enclosure which has airborneacoustic energy. The airborne acoustic energy conversion device 80 canbe supported in the gaseous fluid by mounts or the like, not shown, orsupported in the medium by any suitable means.

Acoustic energy in the air or the like surrounding the airborne acousticenergy conversion device 80 for purposes here is assumed to be in energywave form. The particular fluid medium enclosed in the envelope 82 isimpedance matched with the air or gaseous fluid outside the envelope inorder to insure transmission of the acoustic energy waves into theenvelope 82. When an acoustic energy wave is transferred into theenvelope 82, it causes molecular motion of electrically conductive fluidmedium in the cavities 86. Motion of the particles in the electricallyconductive fluid in the influence of the magnetic field created by themagnets 88 operates similar to that described above with thestructureborne acoustic energy conversion device 10 and converts theacoustic energy into thermal energy. As thermal energy is created in theelectrically conductive fluid medium by the conversion device 80, it istransferred to the walls 90, 92 and 94 of the envelope and dissipatedfrom them to the surroundings. It is further noted that this device maybe so constructed to accept acoustic energy from any source gaseous,liquid, or solid.

A third preferred specific embodiment of this invention is thefluidborne acoustic energy conversion device shown in FIGS. 7, 8 and 9of the drawings. The fluidborne acoustic energy conversion device isgenerally indicated at and includes a cylindrical housing 102 with aninner conduit 104 to pass fluid and sensitizer elements 106 around theinner conduit 104. The cylindrical housing 102 is an elongated barrel108 with a split end cap retaining ring 110 secured in its ends holdingend caps 112 in the end portions of the barrel 108. The split ring 110is preferably held to the end caps 112 by bolts 114 to insure its properplacement. The end caps 112 have an O-ring seal 116 on their perimeterto seal them with the barrel 108 and they have a passageway throughtheir center with an outer coupling 118 on the outside to join a fluidsupply conduit 120 and an inner coupling 122 on the inside to join theinner conduit 104. The inner conduit 104 is an acoustically clearmembrane used to separate the electrically condutive fluid and theacoustic energy carrying fluid. The membrane conduit 104 is held in afluid tight seal with the inner end cap couplings 122 by compressionrings 124.

The sensitizer elements 106 extend radially from the membrane conduit104 to the inner wall of the barrel 108 as can be seen in FIGS. 7 and 9.The sensitizer elements 106 are preferably filaments supported at thebarrel wall 108 similar to the band 70 and guide 68 support shown inFIG. 3 and described in detail with the structureborne acoustic energyconversion device of this invention and have spacer members 126 betweenthe bands 70. The sensitizer elements 106 are preferably supported atthe membrane conduit 104 by looping through its outer portion a detailnot explicitly shown in the drawings. The preferred radial positioningof the sensitizer elements 106 is shown in FIG. 9 with the filaments 56looped through the membrane 104 to the depth of the dotted line. Thisconstruction allows for minimal obstruction of acoustic energy by thesensitizer elements 106. The sensitizer elements 106 are energizedthrough a power line 128 connected to an electrical coupling 130 on anend cap 112 which is connected to the end filaments as shown in FIG. 7.

In order to optimize the conversion of acoustic energy of the fluidborneacoustic energy conversion device 100, the direct transmission ofacoustic energy through the structure of the device is to be minimized.This optimization is to be done in several ways as described supra;other ways are by impedance mismatching the structural elements and theuse of soundisolating materials where practical. The end caps 112 are tobe acoustically isolated from one another and from the barrel 108 tominimize the transmission of acoustic energy between them. The combinedacoustic properties of the electrically conductive fluid and the conduitmembrane 104 are adjusted for an impedance match with the supply fluidpassing through the device in the conduit membrane. Matching propertiesof the supply fluid, membrane conduit 104 and the electricallyconductive fluid cause a maximum amount of acoustic energy to betransmitted from the supply fluid to the electrically conductive fluid.Whether theselected fluids are liquid or gaseous depends on theiracoustic properties and necessarily upon the supply fluid. Anotherfactor affecting the efficiency of the fluidborne acoustic energyconversion device 10 is the sensitizer elements which are designed toproduce a maximum electrical field strength and thereby cause a maximumpower loss within the magnetic field it creates.

In operation the fluidborne acoustic energy conversion device 10 isconnected in a fluid piping system by the fluid supply conduit 120. Thefluid supply conduit 120 carries fluid containing acoustic energy andcan enter the device from either end. The sensitizer elements 106 areenergized through the power line 128 by a direct current power supply toestablish a magnetic field in the electrically conductive fluid. Theelectrically conductive fluid is activated by the acoustic energytransmitted to it through the membrane conduit 104 and cause particlemotion in it which generates electrical eddy currents. The electricaleddy currents are converted to thermal energy due to the power loss asthey move in the electrically conductive fluid. Thermal energy of theelectrically conductive fluid is dissipated from it through the housing102 to the surroundtags.

A fourth preferred specific embodiment of this invention is the linearsonar acoustic energy conversion device and associated apparatus whichis shown in FIGS. l0, l1 and 12. The linear sonar acoustic energyconversion device is shown generally in FIG. 10, indicated at 150, andincludes a plurality of pick-up units 152 in an enclosure 154 filledwith an electrically conductive fluid. The pick-up units 152 areindividually connected to preamplifiers 156 which are in turn connectedto the detection and analysis equipment shown in FIG. 12. The linearsonar device embodiment of this invention is to provide a means ofanalysis and detection of the acoustic energy conversion and provide ameans of converting acoustic energy to thermal energy.

The enclosure 154 is preferably constructed of acoustically clearmaterial to isolate all other elements of the linear sonar conversiondevice 150 from the surrounding fluid. The pick-up units 152 have aspherical shell 158 of acoustically clear material with a post-coilassembly 160 mounted therein extending into the inner cavity of theshell 158 and a power and signal conductor 162 extending through theshell 158. The pick-up units 152 can be constructed with more than onepostcoil assembly therein, but for description purposes here only one isshown. The pick-up units 152 contain the electrically conductive fluidsealed inside the shell 158. A shell mounted connector 164 serves toconnect the power line 162 and the detector coil to the preamplifierunits 156 via an electrical cable 166. It is to be noted that whereseveral signals are to be transmitted as here, they can be multiplexedand sent on a single line instead of multiple lines. The power line 162is preferably a straight wire positioned through the center of the shell158 and has another wire 168 connecting it to the connector 164. Thepost-coil assembly 160 is a post 170 of acoustically clear materialextending radially into the shell 158 with a detector coil 172 mountedon its inner end and connected by leads 174 to the connector 164. Thedetector coil 172 can function to detect electrical eddy-currentactivity in the electrically conductive fluid in the presence of theelectromagnetic field generated by the power line 162. Where the pickupunit has a plurality of detector coils, they can be used to analyze wavemotion and other characteristics of the device requiring cooperatingdetectors. Signals from the detector coils 172 are amplified by theseparate preamplifiers 156 connected to each pick-up unit 152, then thesignal goes by a signal line 176, as the signal detector input to theapparatus shown diagrammatically in FIG. 12.

In order to optimize the conversion of energy by this device, theacoustical properties of the electrically conductive fluid, the shell158, the conductive fluid medium around the pick-up units 152 and thematerial of the enclosure 154 must be matched so a maximum of acousticenergy is transmitted to the electrically conductive fluid inside theshell 158. The materials of the enclosure 154 and the shell 158 arenecessarily substantially acoustically clear to pass a maximum ofenergy. The preamplifiers 156 shown in the enclosure are necessarilyshielded so as not to interfere with the acoustic energy transmissionsor electromagnetic field. the specific fluids used in this device willnecessarily depend on the fluid surrounding the enclosure and the otherfactors as described supra.

in operation of the linear sonar acoustic energy conversion device 150of this invention, the electromagnetic field is generated by the powerline 162 and the enclosure 154 with the fluid medium in it passesacoustic energy to the pick-up units 152. The enclosure 154 can beplaced in a fluid medium so as to receive acoustic energy from somesource. Since the pick-up units and the enclosure are designed to passacoustic energy, the acoustic energy around the enclosures 154 is passedthrough them to the pick-up units 152.

Acoustic energy passing through the pick-up unit shells causes molecularparticle motion of the electrically conductive fluid in the shell; thisin turn generates electrical eddy currents as described supra. Theelectrical eddy currents are dissipated in the electrically conductivefluid due to its omic resistance and are converted to thermal energy.

The block diagram shown in FIG. 12 includes sufficient elements believedto be necessary for analyzing sonar data that can be taken from thepick-up units in the linear sonar acoustic energy conversion device. Theanalytical equipment indicated is designed to receive data from severalpick-up units 152 and store the data separately then retrieve anyportion of it for analysis later. It is to be understood theseanalytical elements are presented as an illustration of a techniqueusable to analyze sonar data obtainable from the acoustic energyconversion devices of this invention.

The block diagram of FIG. 12 shows an arrangement of equipment which istypically used in the analysis of sonar data. The function of theelements shown in the block diagram and their function are brieflydescribed in the following. The carrier frequency generator andpreamplifier imposes a different carrier frequency on the separateinputs received from the detector coils 172. The power supply furnishesthe proper operating powers and voltages for the equipment. It is to benoted the preamplifiers 156 and other amplifiers are necessarilyproperly mis-matched to prevent cross talk between them. The lineisolation and amplifier element boosts the input signal strength andprotects against short circuits in the input signals. The tape deckelement records all signals for permanent storage so they can be usedlater as desired. The spectrum analysis element analyzes the inputsignal without the carrier frequency for characteristics such asstrength, harmonics and other appropriate characteristics. The channelselection and time code unit element generates a time code signaltransmitted to the tape deck element to be used for sequencing andindexing the data. The channel isolation unit element is used to isolatethe input signal from any specific pick-up unit 152 and transmit thatsignal to the memory control and memory element. The memory control andmemory element is the data storage unit of the computer and stores datafor use by it. The computer analyzes data stored in the memory controland memory unit to determine and evaluate the signals for properties ofacoustic reflection, absorption, etc. The control and display element islinked to the computer to control it and to display the calculatedresultant data for observation and interpretation.

In the use and operation of the acoustic energy conversion device ofthis invention and the preferred specific embodiments of it disclosedherein, it is seen that same provides a device to convert acousticalenergy to thermal energy. The preferred specific embodiments of theconversion device provide means to convert acoustical energy to thermalenergy whether the acoustical energy is carried to the device in astructural member or in a fluid. Additionally, the acoustic energyconversion device provides a device which can be used to generate,detect and analyze sonar information as illustrated in the linear sonarconversion device embodiment.

As will be apparent from the foregoing description of the applicantsacoustic energy conversion device, relatively simple means have beenprovided to convert acoustical energy into thermal energy. Theconversion devices are relatively simple in construction and are adaptedto convert acoustic energy that is transmitted in structural members andin fluids to thermal energy. The preferred specific embodiments of theconversion devices are simple to use and can be used in a wide varietyof applications to reduce the acoustic energy content of a fluid or astructure by converting it to thermal energy and for analysis of sonarcharacteristics and data.

While the invention has been described in conjunction with preferredspecific embodiments thereof, it will be understood that thisdescription is intended to illustrate and not to limit the scope of theinvention, which is defined by the following claims.

1 claim:

1. A method of converting acoustic energy to other forms of energy,comprising:

a. establishing a magnetic field in an electrically conductive fluidmedium,

b. passing acoustic energy from a source of same into said fluid mediumhaving acoustic energy waves being opposed in movement by forces of saidmagnetic field, and

c. therein converting said acoustic energy first into electrical energyand second into thermal energy.

2. The method of claim 1, wherein, said magnetic field is established orgenerated from within said fluid medium.

3. The method of claim 1, wherein:

a. said magnetic field is established or generated primarily within anappropriate electrically conductive fluid medium,

b. said acoustic energy is generated mechanically or naturally, and

c. said thermal energy is passed as such from said fluid medium.

4. The method of claim 3, wherein:

a. said acoustic energy is transmitted to said fluid medium bymechanical means,

b. said fluid medium is mechanically isolated so as to receivesubstantially all said acoustic energy,

c. said energy is generated in said fluid medium, and

d. said thermal energy is passed from said fluid medium by conduction,convection, radiation, or any combination thereof.

5. The method of claim 4, wherein:

a. said fluid medium is ionized for optimum electrical conductivity,

b. the bulk modulus and specific weight of said fluid are adjusted formaximum conversion of acoustic energy, and

c. said fluid is an organic or inorganic liquid.

6. The method of claim 3, wherein:

a. said acoustic energy is established in a second fluid medium,

b. said acoustic energy is transmitted to said first fluid medium bysaid second fluid medium,

c. said thermal energy is generated in said first fluid medium, and

d. said thermal energy is transferred from said first fluid medium byconduction, convection, radiation or any combination thereof.

7. The method of claim 6, wherein:

a. said first fluid medium is ionized for optimum electricalconductivity,

b. the bulk modulus and specific weight of said first fluid are adjustedoptimumized for maximum conversion of acoustic energy,

c. said first fluid is organic or inorganic, and

d. said second fluid medium is a conductor of acoustic energy.

8. The method of claim 7 wherein, said second fluid medium is a liquid.

9. The method of claim 7, wherein, said second fluid medium is a gas.

10. The method of claim 3, wherein:

a. said acoustic energy is established in a second fluid medium,

b. said second fluid medium surrounds said first fluid medium,

c. said acoustic energy is transmitted to said first fluid mediumthrough said second fluid medium, and

d. said thermal energy is generated in said first fluid medium andtransferred from same said first fluid medium to said second fluidmedium.

11. The method of claim 10, wherein:

a. said first fluid medium is ionized for optimum electricalconductivity,

b. the bulk modulus and specific weight of said first fluid are adjustedfor maximum conversion of acoustic energy,

0. said first fluid is organic or inorganic, and

d. said second fluid medium is a conductor of acoustic energy.

12. The method of claim 11, wherein, said second fluid medium is aliquid.

13. The method of claim 11, wherein, said second fluid medium is a gas.

14. The method of claim 3, wherein:

a. said acoustic energy is established in a second fluid medium,

b. said acoustic energy is transferred from said second fluid medium tosaid first fluid medium,

0. said acoustic energy is converted to electrical energy in said firstfluid medium,

d. said electrical energy is converted to thermal energy in said firstfluid medium,

c. said thermal energy is transferred to said second fluid medium byconduction, convection, radiation, or any combination thereof, and

f. said other form of energy is detectable in said first fluid mediumfor purposes of analysis.

15. The method of claim 14, wherein:

a. said first fluid medium is ionized for optimum electricalconductivity,

b. the bulk modulus and specific weight of said first fluid are adjustedfor maximum conversion of acoustic energy,

c. said first fluid is an organic or inorganic fluid, and

d. said second fluid is fresh water, or seawater, or any combinationthereof.

16. An acoustic energy conversion device, comprising:

a. an electrically conductive fluid medium,

b. a magnetic field producing means to produce a magnetic field actingon said electrically conductive fluid medium,

0. a source of acoustic energy, and

d. means to receive acoustic energy from said source of same and passsaid energy into said fluid medium to produce acoustical energy sourcewaves in a direction of travel oppositely orientated relative to linesof flux of said magnetic field producing means,

said acoustic energy conversion device adapted to convert acousticenergy into thermal energy by introducing acoustic energy into saidelectrically conductive fluid medium under the influence of a magneticfield.

17. The device of claim 16, wherein:

a. said electrically conductive fluid medium is enclosed in a container,

b. said source of acoustic energy generates sonic waves to be introducedinto said device,

0. said device has a diaphragm to receive sonic waves mounted inappropriate relation to said container to pass said sonic waves intosaid electrically conductive fluid medium,

d. said magnetic field acts through a portion of said fluid medium,

e. said foundation mount means is secured to a substantially immovablesurface and has a cylindrical enclosure with one closed end and has saidtransmitter member mounted at the other end thereof,

f. said cavity-is cylindrical and has said plurality of filament membersmounted at the inner wall of said cavity extending transverselythereacross in one direction, with said transmitter member at one end ofsaid cavity and said reflector surface at the opposite end of saidcavity,

g. said means to acoustically isolate said transmitter member from saidfoundation mount means is a second wall in contact with and between saidcavity wall and said foundation mount means sidewall constructed to bean impedance mismatch between said transmitter member and saidfoundation mount means,

h. said transmitter member is a piston movably mounted within saidcylindrical cavity wall in one end portion thereof,

. said reflector surface is a concavely curved surface mounted withinsaid cylindrical cavity wall at one end thereof constructed to beacoustically reflective in order to reflect acoustic energy that reachesthat end of said cavity back toward said transmitter piston at theopposite end of said cylindrical cavity, and

j. said plurality of filament members are parallel to one anothersecured to an electrically insulated and acoustically clear mount atsaid cavity wall connected to one another arranged in a plurality oftransverse layers speed longitudinally through said cavity, andconnected to an external direct current power source.

18. The device of claim 16, wherein:

a. said electrically conductive fluid is a readily electricallyexcitable fluid,

b. said magnetic field producing means is adapted to produce saidmagnetic field generally homogeneously,

c. said means to transfer acoustic energy to said fluid medium is anacoustically permeable to container adapted to contain said fluidmedium,

d. said source of acoustic energy to generate said sonic waves to passthrough said container, and

c. said means to transfer thermal energy from said fluid medium is aportion of said container having a high coefficient of heat transfer.

19. The deivce of claim 16, wherein:

a. said means to receive acoustic energy and pass same is anacoustically permeable container,

b. said container has a cavity to contain said electrically conductivefluid medium,

c. said magnetic field producing means has a filament within said cavityto carry an electrical current and thereby produce said magnetic field,

d. said acoustically permeable container has a transmitting member incontact with said electrically conductive fluid medium to transmitacoustic energy into said electrically conductive fluid medium,

e. said container means has a foundation mount means to support saiddevice and means to acoustically isolate said transmitter member fromsaid foundation mount means,

f. said magnetic field producing means has a plurality of said filamentswithin said cavity,

g. said transmitter member is rigidly mounted with a structural memberto transmit acoustical energy to said transmitter member; and

h. said means to receive acoustic energy has a reflector surface in saidcavity in contact with said electrically conductive fluid medium toreceive a portion of the transmitted acoustic energy from saidtransmitting member after it passes through said fluid medium andreflect same back through said electrically conductive fluid medium.

20. The deivce of claim 16, wherein:

a. said means to receive acoustic energy and pass same is anacoustically permeable container,

b. said container has a cavity to contain said electrically conductivefluid medium,

c. said magnetic field producing means has a filament in said cavity tocarry electrical current and produce said magnetic field,

d. said means to receive acoustic energy is an acoustically permeablemembrane in contact with said electrically conductive fluid medium and asecond fluid in contact with said membrane,

c. said source of acoustic energy is said second fluid,

and

f. said means to transfer thermal energy from said fluid medium is saidcontainer.

21. The deivce of claim 20, wherein:

a. said container means has an elongated walled housing with saidmembrane cylindrically shaped and mounted centrally in said elongatedhousing forming said cavity to contain said electrically conductivefluid between said membrane and said housing wall,

b. said elongated housing has end caps mounted in the end portionsthereof and mounted with said membrane adapted to attach a conduit topass said second fluid through said acoustically permeable membrane,

c. said end caps are mounted with said elongated housing so as to beacoustically isolated from said membrane and acoustically isolated fromsaid housing wall, and

d. a plurality of said filament members are secured to said elongatedhousing wall by an acoustically clear mount and are connected togetherand to an external electrical power source.

22. The device of claim 21 wherein:

a. said filament members are mounted with said membrane and extendradially therefrom to said acoustically clear mount at said housingwall,

b. said filament members are arranged in a plurality of layers spacedalong and transverse to said elongated housing, and

c. said end caps are mounted on the inside of said housing wall with aseal therearound to close and seal said cavity.

23. The device of claim 16, wherein:

a. said means to receive acoustic energy and pass same is anacoustically permeable container,

b. said container means has a cavity to contain said electricallyconductive fluid medium,

0. said magnetic field producing means has a permanent magnet mountedwith said container means to produce said magnetic field,

(1. said acoustic energy receiving means is an acoustically permeablemembarne forming the outer portion of said container to separate saidelectrically conductive fluid medium in said cavity from a second fluidmedium surrounding said container and adapted to pass acoustical energyfrom said second fluid medium to said electrically conductive fluidmedium, and

c. said source of acoustic energy is through said second fluid medium.

24. The device of claim 23, wherein:

a. said container has a plurality of said cavities therein separated bya plurality of acoustically permeable partitions,

b. said paratitions have a plurality of said permanent magnets securedthereto to produce said magnetic field, and

c. said partiions are attached to said membrane so as to be acousticallyisolated from same and said magnets are attached to said partitions soas to be acoustically isolated from said partitions.

25. The devcie of claim 24, wherein:

a. said container has an elongated rectangular shape with said cavitieselongated,

b. said membrane is integrally attached to and covers said partitionsand forms the outer covering of said container contactable with saidsecond fluid medium,

c. said plurality of partitions are similar to one another and parallelymounted in said container means to said cavities are similar to size andshape, and have said magnets mounted therealong the elongated axis ofsaid partitions, and

d. said electrically conductive fluid medium and said second fluidmedium are gaseous fluid mediums.

26. The device of claim 24, wherein:

a. said means to receive acoustic energy and pass same is anacoustically permeable container,

b. said container has a cavity to contain said electrically conductivefluid medium,

said magnetic field producing means has a wire conductor passing throughsaid cavity to produce said magnetic field,

d. said acoustic energy receiving means is an acoustically permeable andspherically shaped membrane enclosing said cavity to separate saidelectrically conductive fluid medium inside said cavity means from asecond fluid medium surounding said spherical membrane,

. said container means has a closed envelope means 27. The device ofclaim 26, wherein:

a. said wire conductor passes through a major axis of said sphericallyshaped membrane,

b. said envelope means has a plurality of said spherical membranescontained therein,

c. said spherical membrane has a detector coil mounted therein to detectelectrical currents, so as to be usable by sonar analysis equipment, and

d. said means to transfer thermal energy is said envelope means.

28. The device of claim 27, wherein:

a. said plurality of spherical membranes have the same said wireconductor passing through them to generate said magnetic field, and

b. said detector coil is mounted in proper relation to said wireconductor to receive electrical energy from it through the electricallyconductive fluid.

f STATES PATENT oi Ic .CERTIFICATE O CORRECTION J f fi M 0, 9 DatedlSeptember 18 1973 It is cei'fif ied that error appears in theabove-idefitified patent anj d that said Lepters Patent are herebycorrected as shown below:

Column 2,- j, l}i ne 55, "field's" should read fluid COIUIIIIICL 4;li1ie46,Q"irrg) shot 11d read energy Column 9, line 3,"'cond1itiv e"should read E condl ciiiro ,j' co lumn 10, iine v67, "the"" s' 1o1i1 droad Th 15 poiagraph c,

'fifiid, econd oooufihce, should read 1 'iquid C1aim 17, f par ag raphj. lirioiSQ spced" sholiid read 6 spaced Claim 18, i paiagr aph c, I ine Z, oancel "to"; Claim 19', line 1-, "deivce" should read' Yic 1eyieClaim liifneji l, "de ivce" should read 1 devi a 23, paragraph Iin e 2,"'mmbarne" s hould i'o ad" Claim 24, oar agrap h B,."1ine:1 artitionfl i1 S aun-"re d" pai t ition s Claimi z slin e 1,v"' i ev cie" Shouldi I It re a d o Claim/24 p 'ag'rafi li i c1 line 11 partiions" I should readp,ar titions i v i o w v i Signed and sealed th s 27th day of August1974.

. ftsfiALl 2 Attest:

moor-M; GIBSONQJKI I i c. MARSHAL-L] DANN "Attesting Offi'c or'f 1 ICommissioner o-f Patents'

1. A method of converting acoustic energy to other forms of energy,comprising: a. establishing a magnetic field in an electricallyconductive fluid medium, b. passing acoustic energy from a source ofsame into said fluid medium having acoustic energy waves being opposedin movement by forces of said magnetic field, and c. therein convertingsaid acoustic energy first into electrical energy and second intothermal energy.
 2. The method of claim 1, wherein, said magnetic fieldis established or generated from within said fluid medium.
 3. The methodof claim 1, wherein: a. said magnetic field is established or generatedprimarily within an appropriate electrically conductive fluid medium, b.said acoustic energy is generated mechanically or naturally, and c. saidthermal energy is passed as such from said fluid medium.
 4. The methodof claim 3, wherein: a. said acoustic energy is transmitted to saidfluid medium by mechanical means, b. said fluid medium is mechanicallyisolated so as to receive substantially all said acoustic energy, c.said energy is generated in said fluid medium, and d. said thermalenergy is passed from said fluid medium by conduction, convection,radiation, or any combination thereof.
 5. The method of claim 4,wherein: a. said fluid medium is ionized for optimum electricalconductivity, b. the bulk modulus and specific weight of said fluid areadjusted for maximum conversion of acoustic energy, and c. said fluid isan organic or inorganic liquid.
 6. The method of claim 3, wherein: a.said acoustic energy is established in a second fluid medium, b. saidacoustic energy is transmitted to said first fluid medium by said secondfluid medium, c. said thermal energy is generated in said first fluidmedium, and d. said thermal energy is transferred from said first fluidmedium by conduction, convection, radiation or any combination thereof.7. The method of claim 6, wherein: a. said first fluid medium is ionizedfor optimum electrical conductivity, b. the bulk modulus and specificweight of said first fluid are adjusted optimumized for maximumconversion of acoustic energy, c. said first fluid is organic orinorganic, and d. said second fluid medium is a conductor of acousticenergy.
 8. The method of claim 7 wherein, said second fluid medium is aliquid.
 9. The method of claim 7, wherein, said second fluid medium is agas.
 10. The method of claim 3, wherein: a. said acoustic energy isestablished in a second fluid medium, b. said second fluid mediumsurrounds said first fluid medium, c. said acoustic energy istransmitted to said first fluid medium through said second fluid medium,and d. said thermal energy is generated in said first fluid medium andtransferred from same said first fluid medium to said second fluidmedium.
 11. The method of claim 10, wherein: a. said first fluid mediumis ionized for optimum electrical conductivity, b. the bulk modulus andspecific weight of said first fluid are adjusted for maximum conversionof acoustic energy, c. said first fluid is organic or inorganic, and d.said second fluid medium is a conductor of acoustic energy.
 12. Themethod of claim 11, wherein, said second fluid medium is a liquid. 13.The method of claim 11, wherein, said second fluid medium is a gas. 14.The method of claim 3, wherein: a. said acoustic energy is establishedin a second fluid medium, b. said acoustic energy is transferred fromsaid second fluid medium to said first fluid medium, c. said acousticenergy is converted to electrical energy in said first fluid medium, d.said electrical energy is converted to thermal energy in said firstfluid medium, e. said thermal energy is transferred to said second fluidmedium by conduction, convection, radiation, or any combination thereof,and f. said other form of energy is detectable in said first fluidmedium for purposes of analysis.
 15. The method of claim 14, wherein: a.said first fluid medium is ionized for optimum electrical conductivity,b. the bulk modulus and specific weight of said first fluid are adjustedfor maximum conversion of acoustic energy, c. said first fluid is anorganic or inorganic fluid, and d. said second fluid is fresh water, orseawater, or any combination thereof.
 16. An acoustic energy conversiondevice, comprising: a. an electrically conductive fluid medium, b. amagnetic field producing means to produce a magnetic field acting onsaid electrically conductive fluid medium, c. a source of acousticenergy, and d. means to receive acoustic energy from said source of sameand pass said energy into said fluid medium to produce acoustical energysource waves in a direction of travel oppositely orientated relative tolines of flux of said magnetic field producing means, said acousticenergy conversion device adapted to convert acoustic energy into thermalenergy by introducing acoustic energy into said electrically conductivefluid medium under the influence of a magnetic field.
 17. The device ofclaim 16, wherein: a. said electrically conductive fluid medium isenclosed in a container, b. said source of acoustic energy generatessonic waves to be introduced into said device, c. said device has adiaphragm to receive sonic waves mounted in appropriate relation to saidcontainer to pass said sonic waves into said electrically conductivefluid medium, d. said magnetic field acts through a portion of saidfluid medium, e. said foundation mount means is secured to asubstantially immovable surface and has a cylindrical enclosure with oneclosed end and has said transmitter member mounted at the other endthereof, f. said cavity is cylindrical and has said plurality offilament members mounted at the inner wall of said cavity extendingtransversely thereacross in one direction, with said transmitter memberat one end of said cavity and said reflector surface at the opposite endof said cavity, g. said means to acoustically isolate said transmittermember from said foundation mount means is a second wall in contact withand between said cavity wall and said foundation mount means sidewallconstructed to be an impedance mismatch between said transmitter memberand said foundation mount means, h. said transmitter member is a pistonmovably mounted within said cylindrical cavity wall in one end portionthereof, i. said reflector surface is a concavely curved surface mountedwithin said cylindrical cavity wall at one end thereof constructed to beacoustically reflective in order to reflect acoustic energy that reachesthat end of said cavity back toward said transmitter piston at theopposite end of said cylindrical cavity, and j. said plurality offilament membeRs are parallel to one another secured to an electricallyinsulated and acoustically clear mount at said cavity wall connected toone another arranged in a plurality of transverse layers spcedlongitudinally through said cavity, and connected to an external directcurrent power source.
 18. The device of claim 16, wherein: a. saidelectrically conductive fluid is a readily electrically excitable fluid,b. said magnetic field producing means is adapted to produce saidmagnetic field generally homogeneously, c. said means to transferacoustic energy to said fluid medium is an acoustically permeable tocontainer adapted to contain said fluid medium, d. said source ofacoustic energy to generate said sonic waves to pass through saidcontainer, and e. said means to transfer thermal energy from said fluidmedium is a portion of said container having a high coefficient of heattransfer.
 19. The deivce of claim 16, wherein: a. said means to receiveacoustic energy and pass same is an acoustically permeable container, b.said container has a cavity to contain said electrically conductivefluid medium, c. said magnetic field producing means has a filamentwithin said cavity to carry an electrical current and thereby producesaid magnetic field, d. said acoustically permeable container has atransmitting member in contact with said electrically conductive fluidmedium to transmit acoustic energy into said electrically conductivefluid medium, e. said container means has a foundation mount means tosupport said device and means to acoustically isolate said transmittermember from said foundation mount means, f. said magnetic fieldproducing means has a plurality of said filaments within said cavity, g.said transmitter member is rigidly mounted with a structural member totransmit acoustical energy to said transmitter member; and h. said meansto receive acoustic energy has a reflector surface in said cavity incontact with said electrically conductive fluid medium to receive aportion of the transmitted acoustic energy from said transmitting memberafter it passes through said fluid medium and reflect same back throughsaid electrically conductive fluid medium.
 20. The deivce of claim 16,wherein: a. said means to receive acoustic energy and pass same is anacoustically permeable container, b. said container has a cavity tocontain said electrically conductive fluid medium, c. said magneticfield producing means has a filament in said cavity to carry electricalcurrent and produce said magnetic field, d. said means to receiveacoustic energy is an acoustically permeable membrane in contact withsaid electrically conductive fluid medium and a second fluid in contactwith said membrane, e. said source of acoustic energy is said secondfluid, and f. said means to transfer thermal energy from said fluidmedium is said container.
 21. The deivce of claim 20, wherein: a. saidcontainer means has an elongated walled housing with said membranecylindrically shaped and mounted centrally in said elongated housingforming said cavity to contain said electrically conductive fluidbetween said membrane and said housing wall, b. said elongated housinghas end caps mounted in the end portions thereof and mounted with saidmembrane adapted to attach a conduit to pass said second fluid throughsaid acoustically permeable membrane, c. said end caps are mounted withsaid elongated housing so as to be acoustically isolated from saidmembrane and acoustically isolated from said housing wall, and d. aplurality of said filament members are secured to said elongated housingwall by an acoustically clear mount and are connected together and to anexternal electrical power source.
 22. The device of claim 21 wherein: a.said filament members are mounted with said membrane and extend radiallytherefrom to said acoustically clear mount at said housing wall, b. saidfilament memBers are arranged in a plurality of layers spaced along andtransverse to said elongated housing, and c. said end caps are mountedon the inside of said housing wall with a seal therearound to close andseal said cavity.
 23. The device of claim 16, wherein: a. said means toreceive acoustic energy and pass same is an acoustically permeablecontainer, b. said container means has a cavity to contain saidelectrically conductive fluid medium, c. said magnetic field producingmeans has a permanent magnet mounted with said container means toproduce said magnetic field, d. said acoustic energy receiving means isan acoustically permeable membarne forming the outer portion of saidcontainer to separate said electrically conductive fluid medium in saidcavity from a second fluid medium surrounding said container and adaptedto pass acoustical energy from said second fluid medium to saidelectrically conductive fluid medium, and e. said source of acousticenergy is through said second fluid medium.
 24. The device of claim 23,wherein: a. said container has a plurality of said cavities thereinseparated by a plurality of acoustically permeable partitions, b. saidparatitions have a plurality of said permanent magnets secured theretoto produce said magnetic field, and c. said partiions are attached tosaid membrane so as to be acoustically isolated from same and saidmagnets are attached to said partitions so as to be acousticallyisolated from said partitions.
 25. The devcie of claim 24, wherein: a.said container has an elongated rectangular shape with said cavitieselongated, b. said membrane is integrally attached to and covers saidpartitions and forms the outer covering of said container contactablewith said second fluid medium, c. said plurality of partitions aresimilar to one another and parallely mounted in said container means tosaid cavities are similar to size and shape, and have said magnetsmounted therealong the elongated axis of said partitions, and d. saidelectrically conductive fluid medium and said second fluid medium aregaseous fluid mediums.
 26. The device of claim 24, wherein: a. saidmeans to receive acoustic energy and pass same is an acousticallypermeable container, b. said container has a cavity to contain saidelectrically conductive fluid medium, c. said magnetic field producingmeans has a wire conductor passing through said cavity to produce saidmagnetic field, d. said acoustic energy receiving means is anacoustically permeable and spherically shaped membrane enclosing saidcavity to separate said electrically conductive fluid medium inside saidcavity means from a second fluid medium surounding said sphericalmembrane, e. said container means has a closed envelope means containingsaid second fluid medium and said spherically shaped membrane adapted topass acoustic energy from the surrounding into said second fluid medium,and f. said source of acoustical energy is through said second fluidmedium.
 27. The device of claim 26, wherein: a. said wire conductorpasses through a major axis of said spherically shaped membrane, b. saidenvelope means has a plurality of said spherical membranes containedtherein, c. said spherical membrane has a detector coil mounted thereinto detect electrical currents, so as to be usable by sonar analysisequipment, and d. said means to transfer thermal energy is said envelopemeans.
 28. The device of claim 27, wherein: a. said plurality ofspherical membranes have the same said wire conductor passing throughthem to generate said magnetic field, and b. said detector coil ismounted in proper relation to said wire conductor to receive electricalenergy from it through the electrically conductive fluid.